Cold hardiness & minimum temperature

Is Nepeta racemosa 'Blue Wonder' (Nepeta racemosa 'Blue Wonder')cold hardy? Hardiness zone & min temp

Also called Blue Wonder catmint.

More about nepeta racemosa 'blue wonder'

About Nepeta racemosa 'Blue Wonder'

Nepeta racemosa 'Blue Wonder' · also called Blue Wonder catmint · flowering

A compact, low-growing catmint forming neat mounds of aromatic grey-green leaves topped with deep lavender-blue flower spikes from late spring into summer. 'Blue Wonder' is tidier and smaller than 'Walker's Low', making it ideal for edging, paths, and the front of borders. Drought-tolerant, deer-resistant, and bee-friendly, it reblooms well after a midseason shear.

Cold limit: USDA 3-8 · RHS H7 (-34 to 30°C)

Watch for — Crown rot from wet soil: Heavy, waterlogged ground rots the crown; prioritise drainage and avoid winter wet.

What nepeta racemosa 'blue wonder''s hardiness rating actually means

Yes — nepeta racemosa 'blue wonder' is genuinely cold hardy. Rated RHS H7 and USDA 3-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 3-8 — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly below about −20 °C. Nepeta racemosa 'Blue Wonder' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for nepeta racemosa 'blue wonder' as it gets too cold:

It tolerates winter lows to about −20 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can nepeta racemosa 'blue wonder' go outside or overwinter — and where?

Plant it out within USDA 3-8 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when nepeta racemosa 'blue wonder' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Nepeta racemosa 'Blue Wonder' hardiness — frequently asked questions

Is nepeta racemosa 'blue wonder' cold hardy?

Yes — nepeta racemosa 'blue wonder' is genuinely cold hardy. Rated RHS H7 and USDA 3-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Nepeta racemosa 'Blue Wonder' is hardy across USDA 3-8; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature nepeta racemosa 'blue wonder' can survive?

Minimum survivable temperature is roughly below about −20 °C. Nepeta racemosa 'Blue Wonder' is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is nepeta racemosa 'blue wonder'?

Nepeta racemosa 'Blue Wonder' is rated USDA 3-8 and RHS H7 — Hardy in the severest European continental winters.

Can nepeta racemosa 'blue wonder' survive winter outside?

Plant it out within USDA 3-8 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to nepeta racemosa 'blue wonder' below its minimum temperature?

It tolerates winter lows to about −20 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.